Abstract 19P
Background
Body composition (BoC) is increasingly recognized as a crucial predictive and prognostic factor in patients with cancer. Significant loss of skeletal muscle and high adiposity correlates with poorer oncological results. Our study focused on patients with metastatic breast cancer (MBC) treated with trastuzumab deruxtecan (T-DXd), investigating whether metrics of BoC, including muscle mass and adiposity, are associated with treatment toxicity and response.
Methods
A retrospective observational study was performed, encompassing 48 women diagnosed with MBC, who received T-DXd as an advanced therapy option. BoC metrics were assessed by measuring the cross-sectional area of skeletal muscle, visceral and subcutaneous adipose tissue at the third lumbar vertebra via computed tomography (CT). BoC parameters were examined along with outcomes related to drug toxicity including dose modifications, cessation of therapy, hospitalizations, and overall response rate (ORR).
Results
BoC metrics were significantly associated with treatment toxicity and ORR in patients who received T-DXd. High subcutaneous adipose tissue (SAT) area (cm2) and high visceral adipose tissue (VAT) area (cm2) significantly increased the likelihood of dose reduction compared to the low category (odd ration [OR]=4.91, p=.037 and OR=5.00, p=.038, respectively). Additionally, Higher SAT area (cm2) was associated with lower odds of ORR compared to low SAT cm2 (OR=0.20, p=.046). Moreover, significant associations were found for both low and medium SAT density (Hounsfield units [HU]) versus high SAT density and dose reduction (OR=3.86, p=.048 and OR=6.60, p=.017, respectively). Similar results were seen for low and medium VAT density (HU) as well (OR=9.53, p=.007 and OR=7.22, p=.016, respectively). Lastly, body mass index (BMI) above 25 significantly increased the likelihood of dose reduction (OR=4.49, p=.021).
Conclusions
The study underscores the importance of BoC in patients treated with T-DXd. Our findings suggest that adipose tissue metrics and BMI are critical factors influencing dose reduction and response. This approach could lead to more personalized cancer care, potentially improving the safety and efficacy of treatment.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
S. Strulov Shachar: Other, Institutional, Other, Travel: AstraZeneca. A. Sonnenblick: Financial Interests, Personal and Institutional, Invited Speaker: AstraZeneca. Y. Bar: Other, Personal, Invited Speaker: AstraZeneca. All other authors have declared no conflicts of interest.